**1. Introduction**

Currently, it is necessary to design, create, and use innovative materials with an improved complex of physical, mechanical, and operational properties based on structural and tool materials, ceramics, and topocomposites (materials with functional coatings) to ensure improved performance of critical engineering products (elements of aviation equipment, power plants, turbocompressors, metalworking tools, and others) operating in difficult and variable conditions associated with the impact of increased thermal and power loads that cause high wear rates of contact surfaces. One of the most promising and dynamically developing scientific approaches aimed at solving the above problem, within the framework of which the most authoritative research groups around the world are working, is the development and use of adaptive materials and coatings, characterized by a particular structural–phase state in bulk and close to the surface layers [1–4].

Scientists and specialists use various terms such as adaptive, self-organizing, selfhealing, intelligent, "chameleons" to designate such materials and coatings [5–10]. They have a "common denominator", which means the ability to adapt to operational loads (wear, damage, thermal power conditions, stress–strain state, etc.) with all the variety

**Citation:** Grigoriev, S.N.; Migranov, M.S.; Melnik, Y.A.; Okunkova, A.A.; Fedorov, S.V.; Gurin, V.D.; Volosova, M.A. Application of Adaptive Materials and Coatings to Increase Cutting Tool Performance: Efficiency in the Case of Composite Powder High Speed Steel. *Coatings* **2021**, *11*, 855. https://doi.org/10.3390/ coatings11070855

Received: 30 June 2021 Accepted: 13 July 2021 Published: 16 July 2021

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of existing terms, thereby allowing the functionality of a machine-building product and ensuring the operability of the entire system as a whole [11–14].

Muratore et al., in their research, understand "chameleon" coatings to be adaptive nanocomposite coating materials (solid lubricant with size scales of 10−10–10−<sup>4</sup> m, MoS2 coatings) that adjust their surface composition and morphology by multiple mechanisms for reducing friction and wear intensity in aerospace applications [5]. They were the first to introduce this term. However, earlier works can be found that did not use these terms concerning friction reduction.

Pogrebnyak et al. discussed the structural, phase, and chemical composition of adaptive multicomponent nanocomposite coatings. They conducted review work concerning research of hardness, friction, and wear intensity at elevated temperatures of adaptive coatings and analyzed their adhesive strength [4]. The adaptive coating materials with low friction coefficients and wear rate in a wide temperature range were divided into five groups:


The main disadvantage of these materials (ceramics and metal ceramics, composites) was indicated as poor lubricating properties at room temperature and an unstable friction coefficient in a broad temperature range up to 1000 ◦C. The authors conclude that the problem can be solved only by application of nanocopmpoite coatings with different internal structures based on the obtained material group, such as Al/Au, Mo2N/Ag, TiN/Ag, NbN/Ag, TaN/Ag, CrN/Ag, ZrN/Ag, VN/Ag, and CrAlN/Ag composites.

Zekonyte et al. [15] researched transition metal dichalcogenides (self-adaptive W–S–C coatings), which belong to a small family of solid lubricants with potential to produce an ultralow friction state using friction force microscopy. These materials form well-oriented films on the sliding surface with a thickness of 10 nm with a decrease in friction coefficient when the load increases. The well-ordered tungsten disulfide (WS2) layers (tribolayers that peel off as ultrathin flakes) were formed on the coating surface. The observed nanoscale tribological behavior of WSC coatings replicates a deviation of Amonton's law.

Yuan et al. [16] researched a nanomultilayer TiAlCrSiYN/TiAlCrN that was deposited by physical vapor deposition (PVD) on cemented carbide turning inserts for milling DA718 Inconel. It was shown that an initial short-term cutting speed increase during the runningin stage noticeably improves tool life by formation of protective/lubricious tribo-ceramic films on the friction surface.

Sergevnin [12] studied wear resistance and failure of PVD Ti-Al-Mo-N coatings of 14 μm under different conditions. The coefficient of friction was established as 0.42 and 0.51 at +20 ◦C and 500 ◦C and 0.63, 0.71 for TiAlN coating, respectively. The wear of the cutting inserts in 18 min of operation was reduced by 14% comparing TiAlN coating, when uncoated tool had failure (critical wear of 0.47 mm) after 16 min of turning.

The scientific and technological principles for creating adaptive materials and coatings (AMCs) developed by research groups are highly diverse and mainly specialized for specific engineering products (machine parts and cutting tools) in practice. There are no universal methods and technological approaches. First, it is necessary to assess the specifics of the operational loads experienced by the product in AMC's development and practical application. If the cutting tool is considered an object of research, it should be considered a separate class of machine-building products, the operational loads for which have pronounced distinctive features. The processes of friction and wear in cutting materials proceed under specific conditions in comparison with friction and wear of machine parts:


Today, a large body of knowledge and results of theoretical and experimental research on AMC development and improvement has accumulated to improve the performance of various metal-cutting tool types in a wide range of operating loads. This work aimed to develop an easy-to-understand and capacious classification of AMC options that can improve the machining performance and cutting tool service life. In addition, the authors of the work aimed to assess the effectiveness of one of the technological approaches developed at Moscow State University of Technology "STANKIN" for creating adaptive materials using composite powder high speed steels (CPHSSs) containing refractory compounds such as TiC, TiCN, and Al2O3 for milling 41CrS4 steel. The change in the material characteristics under the influence of external loads and the formation of secondary stable structures (oxides and nitrides), i.e., operating conditions, was shown by conducting metallophysical and tribological studies and operational tests in laboratory conditions.

The novelty of the work is research of adaptive coatings of HSS + TiC, TiCN, and Al2O3 additives systems under conditions of 41CrS4 steel milling at normal temperature and in the conditions of elevated temperatures (600 ◦C), classification of adaptive materials and coatings, and creating a cutting tool made of composite powder high speed steels containing refractory compounds.

The following four types of tool materials:


were researched by temperature field studies using a semiartificial microthermocouple method, frictional interaction high-temperature tribometry, laboratory performance tests, and spectrometry of the surface layer secondary structures. The main findings are:


### *1.1. Cutting Tool Performance and AMC Challenges*

New materials and coatings for tool purposes with improved physical, mechanical, and operational properties are of particular interest for modern machine-building enterprises. A cutting tool with higher efficiency can significantly improve the quality of machined parts and minimize energy and resource consumption for cutting when using expensive multi-axis computer numerical control (CNC) machine tools for high speed machining [20–24]. The operation of such machines is characterized by a high machine hour cost, increased cutting tool heat and power loads due to the need to intensify cutting conditions, and an increase in tool consumption per output unit. The acting loads' level increases many times when difficult-to-machine structural materials are cut. The processes of adhesion–friction interaction on the tool's working surfaces are enhanced, and accelerated wear occurs with a simultaneous deterioration in the dimensional accuracy of the workpiece being processed and an increase in its roughness. In such conditions, the cutting tool requires increased efficiency and operational stability, mainly determining the efficiency of metalworking [25–28].

Although the types of cutting tools, tool materials, operating conditions, and the natures of the acting heat and power loads are highly diverse, they are united by common characteristic features. A wide range of acting loads is primarily determined by the type of material to be machined (carbon and low-alloy structural steels, cast and ductile irons, hardened steels and hard cast irons, heat-resistant Fe-, Ni-, or Co-based and titanium alloys, aluminum alloys, Zn-, Mg-, or Cu-based alloys and non-ferrous metals). Additionally, the most critical operating conditions are the cutting shear thickness or cutting feed, which determines the force impact level (increased during preliminary roughing and low during finishing and semifinishing) and the value of the cutting speed (increased and moderate), which determines the thermal effect level on the cutting tool contact pads. The stability of the loads acting on the cutting tool is also important: constant (with continuous contact of the cutting edges of the tool with the workpiece, for example, during turning) and intermittent (during milling, planing, chiseling, intermittent turning, etc.).

An analysis of the wear options and the reasons for the tool operability loss in practice can assist in formulating a problem set to be addressed by developing and applying AMCs. Thus, despite the variety of operating conditions, all AMC practical tasks can be reduced to the following:


A decrease in the intensity of adhesion of the machined material to the tool's rake and flank faces significantly increases the machined part roughness and reduces the tool resource.
